Family interactions can be important contributors to the development of child psychopathology, yet the mechanisms of influence are understudied, particularly for populations at risk. This prospective longitudinal study addresses differences in whole family interactions in 194 families of young children with and without early-identified developmental risk associated with cognitive delay. The influence of family interactions on children's later externalizing behaviors, internalizing behaviors, and social skills was examined, and developmental risk was tested as a potential moderator of these relations. Results indicated that the presence of cognitive developmental risk was linked to higher levels of family control than in families of typically developing children, but groups did not differ on dimensions of cohesion, warmth, organization, or conflict. Observed cohesion and organization were associated with better social skills for all children, regardless of risk status. Significant interactions emerged, indicating that higher levels of conflict and control were associated with higher levels of behavior problems, but only for families of typically developing children. These findings underscore the importance of family-level assessment in understanding the development of children's behavior and suggest the need for deeper analysis of the nuances of family process over time.